US6673002B2 - Sheet folding apparatus with pivot arm fold rollers - Google Patents

Abstract

A system for folding sheet material, including a fold blade, a fold roller, and a driver for moving at least one of the fold blade and the fold roller along a first path into operative communication with one another. The operative communication causes displacement of the fold roller along a longitudinal axis of the fold blade.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to processing sheet material and, more particularly, to a sheet folding apparatus using pivot arm fold rollers.

2. Background Information

A system for finishing printed sheets into booklets is described in PCT Document No. WO 00/18583 (Trovinger et al.). The Trovinger PCT includes an operation where individual booklet sheets are folded using two drive motor assemblies. A first vertical drive motor assembly operates to immobilize a sheet by pressing it against a fold blade with a folder assembly. This first vertical drive motor assembly moves a set of fold rollers into contact with both the sheet and a longitudinal fold blade. The axes of rotation for the fold rollers are perpendicular to the fold blade used to fold each sheet. A second horizontal drive motor then operates to deform the sheet against the fold blade by reciprocating the set of fold rollers, which have been placed into contact with the sheet, back and forth along the fold blade to in effect crease the sheet. The number and spacing of these rollers are such that during horizontal movement of the fold rollers, at least one fold roller passes over every point along the portion of a sheet where a fold is to be formed.

The system described in the Trovinger PCT uses two separate motors to establish linear motion of fold rollers in two axes to create a fold. The time required to create a fold is the cumulative time of moving a folder assembly vertically and moving the fold rollers horizontally to crease the sheet.

It would be desirable to reduce the apparatus cost and the time required to form a fold in a sheet.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to an apparatus that folds sheet material by displacing fold rollers along a fold blade using pivot arms. In this way, only one motor is required to establish linear motion of fold rollers in two axes to create a fold.

According to one embodiment of the present invention, a system for folding sheet material is provided, comprising a fold blade, a fold roller, and drive means for moving at least one of the fold blade and the fold roller along a first path into operative communication with one another, wherein the operative communication causes displacement of the fold roller along a longitudinal axis of the fold blade.

According to another embodiment of the present invention, a method for folding a sheet of material, comprising the steps of feeding a sheet material into an area between a fold roller and a fold blade, and moving the fold roller and the fold blade relative to one another to form a fold in the sheet using the fold blade, wherein an operative communication between the fold roller and the fold blade causes displacement of the fold roller along a longitudinal axis of the fold blade.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments, when read in conjunction with the accompanying drawings wherein like elements have been represented by like reference numerals and wherein:

FIGS. 1A and 1B illustrate perspective views of a folding apparatus in accordance with an exemplary embodiment of the present invention; and

FIGS. 2A-2C illustrate in side, cutaway view a folding operation in accordance with the exemplary embodiment of FIGS.1A and1B.

DETAILED DESCRIPTION OF THE INVENTION

An system for folding sheet material is represented asfolding apparatus100 in FIGS. 1A and 1B. Theexemplary folding apparatus100 includes a fold blade, such asfold blade104 having a longitudinal axis along the x-axis of FIG.1A.Fold blade104 is shown to be held by ablade holder134, but can alternatively be held by any other stabilizing structure or can be manufactured withblade holder134 as a unitary component.Fold blade104 can be fixed or can alternatively be movable (for example, alongrails128 in the y-axis of FIG. 1A, or any desired axis).Fold blade104 can be made of metal (such as stainless steel) or any other formable material, and can be shaped as a flat strip or can include a rounded shape, these example being non-limiting, of course.

Folding apparatus100 also includes a roller, such as one ofrollers106, which can be any number in quantity. Eachexemplary roller106 rotates about an axis perpendicular to a longitudinal axis of fold blade104 (in the FIG. 1A example, this axis of rotation is in the z-axis).Rollers106 can be made of metal or any other formable material, and can be coated with an elastomeric or deformable material such as an elastomer.Rollers106 can be circular in cross-section (as shown in the figures), or can alternatively have any other cross-sectional shape that can operate withfold blade104 to create a fold in sheet material.

A drive means is provided for moving at least of the fold blade and the at least one roller into operative communication with one another. As referred hereon, “operable communication” means placement of the fold blade and/or the fold roller relative to one another to achieve a desired fold in a sheet material. For example, the operative communication can include the interfacing offold rollers106 withfold blade104, directly or indirectly (i.e., throughsheet material248, FIGS.2A-2C). In the exemplary embodiment shown in FIGS. 1A and 1B, the drive means is represented bydrive assembly112, which includes a lead screw (represented by one of lead screws128), where a rotation of the lead screw in a first direction is operable to move the fold roller against the fold blade to create a fold in a sheet material.Drive assembly112 also includesmotor114 andbelts132aand132b.Motor114 can be of any conventional type (such as electric, pneumatic, or hydraulic), or can be of any other type. Theexemplary lead screws128 can be rotated bymotor114 viadrive belts132aand132bor alternatively by any other power transmitting element, such as a chain. Also,drive assembly112 can alternatively be formed as any other actuating system, such as, but not limited to, four-bar linkages, slider-crank mechanisms, pulleys and belts, rack and pinions, and linear actuators (e.g., soleniods, linear electric motors, and hydraulic or pneumatic cylinders),

Asmotor114 is driven by a power supply and controlled by, for example, a controller,lead screws128 rotate and causebrackets130 to move along the y-axis, the direction of their movement dependent on the direction of rotation of thelead screws128.Housing102 is connected tobrackets130 byrods126 and thereby translates along the y-axis whenmotor114 is driven.Housing102 can be fixedly attached torods126, or can alternatively be slidable alongrods126 in the x-axis. Such mobility can be useful when adjustingfolding apparatus100 to accommodate a sheet material's feed position.Housing102 has a longitudinal axis in the x-axis and can be made of any formable material, such as, but not limited to, metal or plastic.

In theexemplary folding apparatus100, the operative communication causes displacement of the fold roller along a longitudinal axis of the fold blade. For example, such displacement (e.g., rolling travel) offold rollers106 along a longitudinal axis offold blade104 can be achieved by the use of a pivot arm, such as one ofpivot arms108, where a fold roller is rotatably attached to a first end of the pivot arm. In the embodiment shown in FIGS. 1A and 1B,rollers106 are each rotatably attached viaroller axles142 to one end (i.e., the first end) of apivot arm108. The other ends (i.e., the second ends) of thepivot arms108 are rotatably attached tohousing102 viaarm axles144. Eachpivot arm108 can be identical in length, or can alternatively differ in length. As described below in conjunction with FIGS. 2A-2C, the operative communication results in a pivoting of the arm (e.g., one of pivot arms108) such that the fold roller (e.g., one of fold rollers106) rotates along the longitudinal axis of the fold blade (e.g., fold blade104).

Folding apparatus100 also includes a spring (such as one of arm springs110) attached to the second end of the pivot arm, where the spring forces the fold roller against the fold blade as the fold rollers rotates along the longitudinal axis of the fold blade. In the embodiment shown in FIGS. 1A and 1B, eachspring110 is attached to apivot arm108 and to anarm axle144. When housing102 is advanced such thatrollers106 press againstfold blade104, springs110 maintain pressure againstfold blade104 viarollers106 ashousing102 continues its advancement (this process is described below).Springs110 can be torsion springs or can be in the form of any other biasing components. All of thesprings110 can have identical spring rates, or these rates can differ from onespring110 to the other. Depending on the spring rates used, very high forces in the −y-axis (i.e., towards fold blade104) can be achieved, and sheet material of varying composition and thickness can be folded.

Housing102 includes at least one pinch wheel, such as one ofpinch wheels120, for clamping sheet material against the fold blade, wherein the at least one pinch foot is elastically mounted to the housing. Eachpinch wheel120 is part of apinch assembly136, which includes apinch bracket140, apinch axle138, apinch shaft116, and apinch spring122. Each pinch wheel is rotatably attached to apinch bracket140 via apinch axle138, and each pinch bracket is attached tohousing102 via apinch shaft116 andpinch spring122. Pinchshafts116 permit vertical translation ofpinch assemblies136 during a folding operation. The FIG. 1B example shows fourpinch assemblies136, although this number can alternatively be greater or lesser. Also,pinch assemblies136 can alternatively include pinching components that are not rotatable and are not formed as wheels. For example, the clamping operation ofpinch wheels120 can instead be performed by a non-rotatable pinch foot with a v-shaped groove.

Pinchwheels120 are rotatable aboutpinch axles138 and can be made of any formable material (metal and plastic being non-limiting examples) or of a deformable or elastomeric material. In the embodiment shown in FIGS. 1A and 1B, eachpinch wheel102 has a concave cylindrical contact surface, but this surface can also be a different shape (e.g., convex or flat). Pinch springs122 can be linear, coil springs or can alternatively be any other elastic attaching means. Pinchwheels120 are vertically biased by pinch springs122 such thathousing102 can continue to translate towardsfold blade104 after pinch wheels232 have engaged a sheet againstfold blade104, thereby anchoring it in place during a fold operation.

Housing102 also includes fold flaps, such as twofold flaps118, for forcing a sheet material around the fold blade. Fold flaps118 can be arranged to have any angle between them such thatblade holder134 fits between fold flaps118 during a folding operation. Fold flaps118 can be manufactured withhousing102 as a unitary component or separately fromhousing102, and can be manufactured from the same material ashousing102 or from a different, formable material. Fold flaps118 can be pivotally attached to each other at a pivot point P₁and can also be pivotably biased towards each other by using, for example, flap springs124. This arrangement allows the adjusting of the angle between fold flaps118 to accommodate different sheet material thickness. Alternatively, any other elastic connecting means can be used to bias the fold flaps118 towards one another, or foldflaps118 can be fixedly attached to each other.

The operation of thefolding apparatus100 is illustrated in FIGS. 2A-2C, where the method includes a step of feeding a sheet material into an area between a fold roller and a fold blade. For example,sheet material248 in FIGS. 2A-2C is advanced a predetermined distance into thefolding apparatus200 in the +z or −z direction such thatsheet material248 is positioned between fold rollers206 and foldblade204. FIGS. 1A and 1B illustrate a sheet path SP ofsheet material248 in the −z direction, for example. The predetermined distance can be chosen by the desired width of the booklet and, for example, the location of the sheet in the booklet, as described in the Trovinger PCT.Sheet material248 is positioned acrossfold blade204 such that the location where a fold is desired is placed directly over thefold blade204.

Oncesheet material248 is positioned over thefold blade204,housing102 translates towardssheet material248 and foldblade204 in the −y direction through operation of drive assembly112 (FIGS.1A and1B). FIG. 2A illustrates the instance where initial contact is made between apinch wheel220 andsheet material248. Aline202arepresents the position of the top of housing202 relative to the other components offolding apparatus200. FIGS. 2A-2C illustrate the use of onepinch wheel220, but alternatively any number ofpinch wheels220 can be used.Pinch wheel220 capturessheet material248 againstfold blade204 by the force created by pinch springs222. In an alternative embodiment,pinch wheel220 is not included infolding apparatus200, and its clamping function is instead performed by fold rollers206 themselves.

Whenpinch wheel220 makes its initial contact withsheet material248, fold rollers206 are not yet in contact withsheet material248. FIGS. 2A-2C each illustrate four fold rollers206, but this number can alternatively be less or greater. Distance d₁represent the distance betweenfold rollers206aand206band betweenfold rollers206band206c. Distance d₂represents the distance betweenfold roller206cand206d. Distances d₁and d₂can be identical in length or can be different, as shown in FIGS. 2A-2C. Also, alternatively, the distances betweenfold rollers206aand206band betweenfold rollers206band206ccan be different. In FIG. 2A, all four fold rollers206 and pivotarms208 are shown to be positioned at a default angle θ₁from the y-axis. This is to allow for the rotation ofpivot arms208 aboutarm axles244 when the housing is translated along the y-axis and when the fold rollers206contact sheet material248 or foldblade204. Angle θ₁can be of any angle within the range of around 1 degree to 90 degrees, depending on, for example, the construction and length of sheet material to be folded. Alternatively, each or some of the fold rollers206 can be initially positioned at different angles from one another.

Afterpinch wheel220 securessheet material248,housing102 continues to translate towardsfold blade204 and fold flaps118 (FIGS. 1A and 1B) start to contact and bendsheet material248 around the top offold blade204, as described in the Trovinger PCT.Sheet material248 remains captured betweenpinch wheel220 and thefold blade204. A slack loop can be form insheet material248 by, for example, a paper drive assembly, as described in the Trovinger PCT.

The method also includes the step of moving the fold roller and the fold blade relative to one another to form a fold in the sheet using the fold blade, wherein an operative communication between the fold roller and the fold blade causes displacement of the fold roller along a longitudinal axis of the fold blade. FIG. 2billustrates the instance where fold rollers206 (i.e., the v-shaped grooves of fold rollers206) initially contact the portion ofsheet material248 lying on the top edge offold blade204. At this point, thepinch wheel220 continues to maintain a securing force againstsheet material248 and foldblade204 through the biasing action of the compressedpinch spring222. Also at this point, pivotarms208 have not yet begun to rotate aboutarm axles244. However, as housing202 continues to advance, pivotarms208 rotate aboutarm axles244 in the z-axis, resulting in the rolling of fold rollers206 alongsheet material248 in the +x direction. The biasing force created by arm springs110 ensure that fold rollers206 produce a sharp crease insheet material248 as they roll on and deformsheet material248 aroundfold blade204. Each fold roller206 can include, for example, two roller halves that can be adjusted to accommodate sheet material of varying thickness. For example, roller halves can be biased toward or away from each other with the use of springs.

FIG. 2C illustrates the position ofhousing102 at its furthest advancement towardsfold blade204. At this position, pivotarms208 are each located at a rotational distance θ₂from the y-axis, and fold rollers206 have each traveled a distance d3 in the +x direction (provided thatpivot arms208 all begin at an identical default position and are identical in length). Alternatively, each or some of the fold rollers206 can travel a different distance from the other fold rollers206.

Folding apparatus200 includes multiple fold rollers, as described above, and an initial positioning of the fold rollers is such that movement of one fold roller overlaps the movement of another fold roller. In other words, the default distances d₁and d₂, the lengths ofpivot arms208, and default angles θ₁are all chosen such that the travel of each fold roller206 alongsheet material248 is such that every point along a createdfold246 is contacted and creased by at least one fold roller206. For example, in FIGS. 2A-2C, the distance d₃traveled by each fold roller206a-206cis greater than the initial distance between these fold rollers (i.e., is greater than d₁). In the case offold roller206d, the above characteristics (e.g., pivot arm length, default angle, etc.) are chosen such thatfold roller206dcreases fold246 and moves beyond the edge ofsheet material248 to ensure the integrity of the fold. The above characteristics are also chosen such that the operation ofpinch wheel220 is not interfered. For example, when housing202 reaches its furthest point of advancement, the travel offold roller206c(FIG. 2C) ends at the area on sheet material238 wherepinch wheel220 is positioned. Also, the initial position offold roller206d(FIG. 2A) is such that it begins its travel onsheet material248 at an area directly adjacent to the location ofpinch wheel220. Further,pivot arm208dcan be formed such that its rotation does not contact or interfere withpinch shaft216 andpinch spring222. For example,pivot arm208d(or any other pivot arm) can be formed by one or more components (as shown in FIGS.1A and1B), wherepinch shaft216 andpinch spring222 are positioned between these components.

The above process can be repeated to fullycrease sheet material248 along the length offold246. For example, housing202 can be moved from the position shown in FIG. 2bto the position shown in FIG. 2C multiple times, whilesheet material248 remains secured to foldblade204 bypinch wheel220. The portion portions offold248, due to the fact that fold rollers206 do not roll this area ofsheet material248 againstfold blade204 during a folding operation. When producing a booklet with a sheetwise process, as described in the Trovinger PCT, these pinched portions of a stack ofsheet material248 can be stapled together to form a booklet of folded sheets. Oncefold246 is fully formed insheet material248, housing202 is translated away fromfold blade204 to the position shown in FIG. 2A, i.e., out of the sheet path. In so doing,pinch wheel220 releases foldedsheet material248 fromfold blade204. Folded sheet material can then be ejected from foldingapparatus200 and delivered to a downstream device, such as a sheet-collecting saddle, for example.

The exemplary embodiments of the present invention provide for quicker folding of sheet material at a lower apparatus cost, due to the use of a single motor to drive fold rollers in two axes to create folds in sheet material. In this way, folds can be formed in one smooth motion instead of two reciprocating motions. Exemplary embodiments of the present invention can be modified to include features from any or all of the following copending applications, all filed on even date herewith, the disclosures of which are hereby incorporated by reference in their entirety: Sheet Folding Apparatus, Ser. No. 09/970,730; Thick Media Folding Method, Ser. No. 09/970,748; Variable Media Thickness Folding Method, Ser. No. 09/971,351 and Sheet Folding Apparatus With Rounded Fold Blade, Ser. No. 09/970,840.

It will be appreciated by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restricted. The scope of the invention is indicated by the appended claims rather than the foregoing description and all changes that come within the meaning and range and equivalence thereof are intended to be embraced therein.

Claims (15)

What is claimed is:

1. A method for folding a sheet of material, comprising the steps of:

feeding a sheet material into an area between a fold roller and a fold blade; and

moving the fold roller and the fold blade relative to one another to form a fold in the sheet using the fold blade,

wherein an operative communication between the fold roller and the fold blade displaces the fold roller along a longitudinal axis of the fold blade, and the operative communication pivots at least one fold arm having the fold roller rotatably attached to a first end, the arm being pivotably attached to a housing of a fold apparatus, such that the fold roller rotates along the longitudinal axis of the fold blade.

2. The method ofclaim 1, comprising translating the housing relative to the fold blade.

3. A system for folding sheet material, comprising:

a fold blade;

at least one fold roller;

drive means for moving at least one of the fold blade and each of the at least one fold rollers along a first path into operable communication with one another; and

at least one arm, wherein each arm has one of the at least one fold rollers rotatably attached to a first end and the arm is pivotably attached to a housing of the fold apparatus,

wherein the operative communication causes displacement of each of the at least one fold rollers along a longitudinal axis of the fold blade, and

wherein the operative communication pivots each of the at least one arms such that each of the at least one fold rollers rotates along the longitudinal axis of the fold blade.

4. The system ofclaim 3, wherein the drive means comprises:

a lead screw, wherein a rotation of the lead screw in a first direction is operable to move each of the at least one fold rollers against the fold blade to create a fold in a sheet material.

5. The system ofclaim 3, comprising:

a plurality of springs, one of the plurality of springs attached to a second end of each of the at least one arms, wherein the one spring forces the fold roller of the at least one arm against the fold blade as the fold roller rotates along the longitudinal axis of the fold blade.

6. The system ofclaim 5, wherein the spring is a torsion spring, a compression spring, or an extension spring.

7. The system ofclaim 3, wherein the system comprises multiple fold rollers, and wherein an initial positioning of each of the multiple fold rollers is such that movement of one fold roller overlaps the movement of another fold roller.

8. The system ofclaim 3, wherein the housing is translatable relative to the fold blade.

9. The system ofclaim 3, wherein the drive means is a single drive means.

10. A system for folding sheet material, comprising:

a fold blade;

at least one fold roller;

drive means for moving at least one of the fold blade and each of the at least one fold rollers along a first path into operable communication with one another, wherein the operative communication causes displacement of each of the at least one fold rollers along a longitudinal axis of the fold blade;

at least one arm, wherein each arm has one of the at least one fold rollers rotatably attached to a first end and the arm is pivotably attached to a housing of the fold apparatus; and

a plurality of springs, one of the plurality of springs attached to a second end of each of the at least one arms, wherein the one spring forces the fold roller of the at least one arm against the fold blade as the fold roller rotates along the longitudinal axis of the fold blade.

11. The system ofclaim 10, wherein the drive means comprises:

a lead screw, wherein a rotation of the lead screw in a first direction is operable to move each of the at least one fold rollers against the fold blade to create a fold in a sheet material.

12. The system ofclaim 10, wherein the drive means is a single drive means.

13. The system ofclaim 10, wherein the spring is a torsion spring, a compression spring, or an extension spring.

14. The system ofclaim 10, wherein the system comprises multiple fold rollers, and wherein an initial positioning of each of the multiple fold rollers is such that movement of one fold roller overlaps the movement of another fold roller.

15. The system ofclaim 10, wherein the housing is translatable relative to the fold blade.

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